diff --git a/template/Install-CIToolchain-WinBuild2022.ps1 b/template/Install-CIToolchain-WinBuild2022.ps1
index a45b31f..b175ffd 100644
--- a/template/Install-CIToolchain-WinBuild2022.ps1
+++ b/template/Install-CIToolchain-WinBuild2022.ps1
@@ -280,12 +280,19 @@ function Invoke-DiskCleanup {
     } catch {
         Write-Warning "wuauserv pre-DISM ACL deny skipped (non-fatal): $_"
     }
+    # Use the ScheduledTasks cmdlets (not schtasks.exe): a missing task makes
+    # schtasks write to stderr and exit 1, which — under EAP=Stop and the
+    # exit-code-sensitive cleanup wrapper — leaks $LASTEXITCODE=1 and fails the
+    # whole step. The cmdlets just no-op silently when the task is absent.
     foreach ($t in @(
         '\Microsoft\Windows\WindowsUpdate\Scheduled Start',
         '\Microsoft\Windows\UpdateOrchestrator\Schedule Scan',
         '\Microsoft\Windows\UpdateOrchestrator\Schedule Scan Static Task'
     )) {
-        schtasks /Change /TN $t /Disable 2>&1 | Out-Null
+        $leaf = Split-Path $t -Leaf
+        $path = (Split-Path $t -Parent) + '\'
+        Get-ScheduledTask -TaskPath $path -TaskName $leaf -ErrorAction SilentlyContinue |
+            Disable-ScheduledTask -ErrorAction SilentlyContinue | Out-Null
     }
 
     $sdDownload = 'C:\Windows\SoftwareDistribution\Download'
diff --git a/template/Install-CIToolchain-WinBuild2025.ps1 b/template/Install-CIToolchain-WinBuild2025.ps1
index 82ef2b5..d598193 100644
--- a/template/Install-CIToolchain-WinBuild2025.ps1
+++ b/template/Install-CIToolchain-WinBuild2025.ps1
@@ -281,12 +281,19 @@ function Invoke-DiskCleanup {
     } catch {
         Write-Warning "wuauserv pre-DISM ACL deny skipped (non-fatal): $_"
     }
+    # Use the ScheduledTasks cmdlets (not schtasks.exe): a missing task makes
+    # schtasks write to stderr and exit 1, which — under EAP=Stop and the
+    # exit-code-sensitive cleanup wrapper — leaks $LASTEXITCODE=1 and fails the
+    # whole step. The cmdlets just no-op silently when the task is absent.
     foreach ($t in @(
         '\Microsoft\Windows\WindowsUpdate\Scheduled Start',
         '\Microsoft\Windows\UpdateOrchestrator\Schedule Scan',
         '\Microsoft\Windows\UpdateOrchestrator\Schedule Scan Static Task'
     )) {
-        schtasks /Change /TN $t /Disable 2>&1 | Out-Null
+        $leaf = Split-Path $t -Leaf
+        $path = (Split-Path $t -Parent) + '\'
+        Get-ScheduledTask -TaskPath $path -TaskName $leaf -ErrorAction SilentlyContinue |
+            Disable-ScheduledTask -ErrorAction SilentlyContinue | Out-Null
     }
 
     $sdDownload = 'C:\Windows\SoftwareDistribution\Download'